source: mainline/boot/generic/src/payload.c@ 39916d6

/*
 * SPDX-FileCopyrightText: 2007 Michal Kebrt
 * SPDX-FileCopyrightText: 2018 Jiří Zárevúcky
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <payload.h>

#include <align.h>
#include <printf.h>
#include <arch/arch.h>
#include <tar.h>
#include <gzip.h>
#include <stdbool.h>
#include <memstr.h>
#include <errno.h>
#include <str.h>
#include <halt.h>

static const char *ext(const char *s)
{
        const char *last = s;

        while (*s) {
                if (*s == '.')
                        last = s;

                s++;
        }

        if (*last == '.')
                return last;

        return NULL;
}

static void basename(char *s)
{
        char *e = (char *) ext(s);
        if ((e != NULL) && (str_cmp(e, ".gz") == 0))
                *e = '\0';
}

static bool overlaps(uint8_t *start1, uint8_t *end1,
    uint8_t *start2, uint8_t *end2)
{
        return !(end1 <= start2 || end2 <= start1);
}

static bool extract_component(uint8_t **cstart, uint8_t *cend,
    uint8_t *ustart, uint8_t *uend, uintptr_t actual_ustart,
    void (*clear_cache)(void *, size_t), task_t *task)
{
        const char *name;
        size_t packed_size;

        if (!tar_info(*cstart, cend, &name, &packed_size))
                return false;

        const uint8_t *data = *cstart + TAR_BLOCK_SIZE;
        *cstart += TAR_BLOCK_SIZE + ALIGN_UP(packed_size, TAR_BLOCK_SIZE);

        bool gz = gzip_check(data, packed_size);
        size_t unpacked_size = gz ? gzip_size(data, packed_size) : packed_size;

        /* Components must be page-aligned. */
        uint8_t *new_ustart = (uint8_t *) ALIGN_UP((uintptr_t) ustart, PAGE_SIZE);
        actual_ustart += new_ustart - ustart;
        ustart = new_ustart;
        uint8_t *comp_end = ustart + unpacked_size;

        /* Check limits and overlap. */
        if (overlaps(ustart, comp_end, loader_start, loader_end)) {
                /* Move the component after bootloader. */
                printf("%s would overlap bootloader, moving to %p.\n", name, loader_end);
                uint8_t *new_ustart = (uint8_t *) ALIGN_UP((uintptr_t) loader_end, PAGE_SIZE);
                actual_ustart += new_ustart - ustart;
                ustart = new_ustart;
                comp_end = ustart + unpacked_size;
        }

        if (comp_end > uend) {
                printf("Not enough available memory for remaining components"
                    " (at least %zd more required).\n", comp_end - uend);
                halt();
        }

        printf(" %p|%p: %s image (%zu/%zu bytes)\n", (void *) actual_ustart,
            ustart, name, unpacked_size, packed_size);

        if (task) {
                task->addr = (void *) actual_ustart;
                task->size = unpacked_size;
                str_cpy(task->name, BOOTINFO_TASK_NAME_BUFLEN, name);
                /* Remove .gz extension */
                if (gz)
                        basename(task->name);
        }

        if (gz) {
                int rc = gzip_expand(data, packed_size, ustart, unpacked_size);
                if (rc != EOK) {
                        printf("\n%s: Inflating error %d\n", name, rc);
                        halt();
                }
        } else {
                memcpy(ustart, data, unpacked_size);
        }

        if (clear_cache)
                clear_cache(ustart, unpacked_size);

        return true;
}

/* @return Bytes needed for unpacked payload. */
size_t payload_unpacked_size(void)
{
        size_t sz = 0;
        uint8_t *start = payload_start;
        const char *name;
        size_t packed_size;

        while (tar_info(start, payload_end, &name, &packed_size)) {
                sz = ALIGN_UP(sz, PAGE_SIZE);
                if (gzip_check(start + TAR_BLOCK_SIZE, packed_size))
                        sz += gzip_size(start + TAR_BLOCK_SIZE, packed_size);
                else
                        sz += packed_size;

                start += TAR_BLOCK_SIZE + ALIGN_UP(packed_size, TAR_BLOCK_SIZE);
        }

        return sz;
}

/**
 * Extract the payload (kernel, loader, init binaries and the initrd image).
 *
 * @param bootinfo      Pointer to the structure where the actual placement
 *                      of components is recorded.
 *
 * @param kernel_dest   Address of the kernel in the bootloader's address space.
 *                      Kernel is the only part of the payload that has a fixed
 *                      location and cannot be moved. If the kernel doesn't fit
 *                      or would overlap bootloader, bootloader halts.
 *
 * @param mem_end       End of usable contiguous memory.
 *                      The caller guarantees that the entire area between
 *                      kernel_start and mem_end is free and safe to write to,
 *                      save possibly for the interval [loader_start, loader_end).
 *                      All components are placed in this area. If there is not
 *                      enough space for all components, bootloader halts.
 *
 * @param kernel_start  Address the kernel will have in the kernel's own
 *                      address space.
 *
 * @param clear_cache   Caller-provided function for assuring cache coherence,
 *                      whatever that means for a given platform. May be NULL.
 */
void extract_payload(taskmap_t *tmap, uint8_t *kernel_dest, uint8_t *mem_end,
    uintptr_t kernel_start, void (*clear_cache)(void *, size_t))
{
        task_t task;
        memset(&task, 0, sizeof(task));

        printf("Boot loader: %p -> %p\n", loader_start, loader_end);
        printf("Payload: %p -> %p\n", payload_start, payload_end);
        printf("Kernel load address: %p\n", kernel_dest);
        printf("Kernel start: %p\n", (void *) kernel_start);
        printf("RAM end: %p (%zd bytes available)\n", mem_end,
            mem_end - kernel_dest);

        size_t payload_size = payload_end - payload_start;
        uint8_t *real_payload_start;
        uint8_t *real_payload_end;

        if (overlaps(kernel_dest, mem_end, payload_start, payload_end)) {
                /*
                 * First, move the payload to the very end of available memory,
                 * to make space for the unpacked data.
                 */
                real_payload_start = (uint8_t *) ALIGN_DOWN((uintptr_t)(mem_end - payload_size), PAGE_SIZE);
                real_payload_end = real_payload_start + payload_size;
                memmove(real_payload_start, payload_start, payload_size);

                printf("Moved payload: %p -> %p\n", real_payload_start, real_payload_end);
        } else {
                real_payload_start = payload_start;
                real_payload_end = payload_end;
        }

        printf("\nInflating components ... \n");

        uint8_t *end = mem_end;

        if (real_payload_end > kernel_dest && real_payload_start < mem_end)
                end = real_payload_start;

        /* Kernel is always first. */
        if (!extract_component(&real_payload_start, real_payload_end,
            kernel_dest, end, kernel_start, clear_cache, &task)) {
                printf("There is no kernel.\n");
                halt();
        }

        if ((uintptr_t) task.addr != kernel_start) {
                printf("Couldn't load kernel at the requested address.\n");
                halt();
        }

        tmap->cnt = 0;

        for (int i = 0; i <= TASKMAP_MAX_RECORDS; i++) {
                /*
                 * `task` holds the location and size of the previous component.
                 */
                uintptr_t actual_dest =
                    ALIGN_UP((uintptr_t) task.addr + task.size, PAGE_SIZE);
                uint8_t *dest = kernel_dest + (actual_dest - kernel_start);

                if (real_payload_end > dest && real_payload_start < mem_end)
                        end = real_payload_start;

                if (!extract_component(&real_payload_start, real_payload_end,
                    dest, end, actual_dest, clear_cache, &task))
                        break;

                if (i >= TASKMAP_MAX_RECORDS) {
                        printf("More components than the maximum of %d.\n",
                            TASKMAP_MAX_RECORDS);
                        halt();
                }

                tmap->tasks[i] = task;
                tmap->cnt = i + 1;
        }

        printf("Done.\n");
}